I just got back in town (Zurich) so apologies for not responding sooner. I'd be up for some training or racing but there aren't many events in Switzerland!
As for organized trail runs, I'm not aware of a central site that lists them all. Compared with the US, trail running in Switzerland doesn't seem to be as big an organized activity (in Boulder, Colorado -- as a contrast -- there are trail runs and ultras nearly every weekend!). It's a shame as there are thousands of trails and beautiful venues, just not many organizations making it happen. I have lots of long running routes through the Glarner Alps, Mythens, and Luzern area (it's where we hosted Untamed Switzerland this Spring: www.UntamedAdventure.com/Switzerland
) if you feel up for a day on Pilatus, Stans, etc.
If you're looking for an accredited trail run to earn points towards qualifying for future races, I think there's one in Soll, Austria in the next couple weeks that's well established. It's too far for me to travel to, but it might be worth it to you.